Automobile heating system



1940- H. J. DE N. M COLLUM 2,190,571

AUTOMOBILE HEATING SYSTEM Filed April 6, 1938 2 Sheets-Sheet 1 0 1a a!99 h w Feb 1940- H. J. DE N. MCCOLLUM 2,190,671

AUTOMOBILE HEATING SYSTEM Filed April 6, 1938 2 Sheets-Sheet 2 E lllllll i l l lk HIHIFTIIIHTTIHIIIIHHI IIIIIIIIIHIII III 2 7 I INTAKE MAN/FOLD12006202014 fizzryJDeZ/MZallum 6M7 LQCQMI/M 546 Patented Feb. 20, 1940UNITED STATES PATENT OFFICE ,6 Claims.

My invention relates generally to unit type heaters, and moreparticularly to improved control mechanisms for automobile heaters ofthe internal combustion type. It is an object of my invention toprovidean improved control switch and operating means therefor in whicha thermostatic element is utilized as a switch member and as a means foractuating the control switch.

It is a further object of my invention to provide an improved form ofcontrol mechanism for heaters employing forced air circulation, in whichthe means for forcing the circulation of the air r being heated iscontrolled automatically and independently of the main control device ofthe heater.

Other objects will appear from the following description, referencebeing had to the accompanying drawings, in which:

Figs. 1, 2, and 4 are sectional views of a heater control switch,showing the parts in different positions;

'Fig. 3 is a front elevational view of the control switch, otherportions of the heater being shown in section;

Fig. 5 is a plan view of the heater control switch; and

Fig. 6 is a diagrammatic view of the elements of the heater and theelectrical circuits associated therewith.

The improved control mechanism disclosed and claimed in this applicationis adapted to be used in conjunction with heaters of the type disclosedin my copending applications, Serial No. 61,213, filed January 28, 1936,and Serial No. 120,523, filed January 14, 1937. The important parts ofthe heaters disclosed in the aforesaid applications are diagrammaticallyillustrated in Fig. 6, wherein a casting i0 is provided with acombustion chamber l2 to which a-mixture of fuel and air is suppliedthrough a carbureting device 14. The latter is connected to a suitablesource of liquid fuel by a conduit l6, the source usually being thefloat bowl of the carburetor used to supply the 45 internal combustionengine, when the heater is used on an automobile, although any othersuitable source of liquid fuel may be utilized. The mixture of fuel andair in the combustion chamber l2 is ignited by means of an igniter shownas a high resistance element l8, which may be of nichrome or similarwire and is electrically heated to a temperature sufiicient to causeignition of the mixture in the combustion chamber l2.

The products of combustion flow through passageways formed in areigniter plug 26 into a circuitous passageway 22 formed in a radiatorcasting 24, the passageway terminating at the inlet end of a vacuumcompensating nozzle 26 which is connected by a conduit 28 to the intakemanifold 30 of the automobile engine. In the event that the heater isused for heating enclosures other than an automobile, the passageway 22may be connected with a suitable source of suction, as might be providedby a suction fan or blower. The radiator casting 24 is surrounded by acup-shaped shell 32 which has heat radiating fins 34 securedtherearound. It will be understood that the radiator will generally belocated in the passenger compartment of an automobile and that air fromthe compartment will be circulated downwardly past the radiator by meansof a fan 36 driven by an electric motor 38.

' The operation of the heater is controlled by means of a handle button40 which is secured at the outer end of a valve stem 42, the inner endof which carries a valve 44 cooperable with the mouth of the nozzle 26,the latter forming a seat for the valve.

As best shown in Fig. 1, the stem 42 is guided in a bushing 46 which isthreaded in the combustion chamber casting 24 and is provided with asuitable slot to receive a spring detent 48 engageable with one of threeannular grooves 50; 52,

54, turned in the stem 42'. As shown in Fig. 1, the detent is inengagement with the groove 50, thus holding the valve 44 in its positionin which it is shown in Fig. 6. This is the normal position when theheater is not in operation. When the heater is in full operation, thedetent spring 48 engages the groove 54 as shown in Fig. 2, while whenthe heater is operating for low volume of heated air delivery, the stem42 will be pushed inwardly so that the spring detent 48 engages theannular groove 52. A switch supporting plate 56 is se- ,cured closelyadjacent and in heat conducting contact with the end of the shell 32 bymeans of the bushing 46, the plate 56 being held from rotary movement.about the bushing 46 by a projection 58 struck from the end wall of theshell 32 and engaging in an aperture 66 formed in the plate. to conductheat from the shell 32 and will thus be maintained at substantially thesame temperture as the shell.

A rigid switch arm 62, a flexible switch arm 64, anda bimetalthermostatic switch arm 66 are secured to the supporting plate 56 by apair of rivets 68, each of these switch arms being insulated from theother and from the plate 56 by sheets of insulation 1!], l2, l4, l6, andtubular insulators i6 and 80 surrounding the rivets. A metallic spacer8| lies adjacent the clamped portion of the bimetal switch element 66,and a metallic end plate 82 forms a means for distributing the clampingpressure of the rivets. The insulating strip 1 is preferably of thinmica and extends sufficiently beyond the spacer 8| and the adjacentsurface of the supporting plate 56 to make certain that the thermostaticbimetal switch arm 66 will not at any time come into The plate 56 isthus adapted readilycontact with the'plate 56. This strip 16 is verythin and thus conducts heat to the arm 66 without a great drop intemperature.

Contact points in the form of rivets are secured to the ends of switcharms, there being a contact point 84 for the rigid switch arm 62, acontact 86 secured to the end of the bimetal switch arm 66, and a pairof contacts 88 and 96 carried by and in electrical connection with theflexible switch arm 64. The contact point 96, which is cooperable withthe contact point 86, is carried by a bent strip 92, which is clamped tothe extremity of the switch arm 64 by means of a clip 94. The contactrivet 88 is carried by a bent metallic strip 96 which is likewisesecured to the oifset end of the contact arm 64. A strip 98 ofinsulating ma terial is secured adjacent the extremity of the offsetportion of the switch arm 64. An insulating strip I66 is secured to theinner surface of the resilient switch arm 64 by means of a rivet I62 soas to prevent electrical contact of the latter with the bimetal switcharm 66. A sheet of mica I66 is secured to thesupporting plate 56 byrivets I66, and thus prevents electrical contact between the contact 96or its carrying arm 92 and the switch plate 56.

The flexible switch arm 64 has a terminal I68 which is connected by aconductor II6 with a suitable source of electrical energy, such as abattery II 2 (Fig. 6) representative of the storage battery of anautomobile when the heater is'installed upon an automobile. The currentfrom the battery to the conductor III! may be controlled by a switch II4 which may be the ignition switch or a separate switch, preferablyoperated incidental to the operation of the ignition switch of theautomobile. The rigid switch arm 62 has a terminal I I6 which isconnected by a conductor IIB with the igniter I6, the circuit throughthe latter being completed through the casting I6, which is shown asgrounded. The bimetal switch arm 66 has a terminal I26 (Fig. 3) which isconnected by a conductor I22 with the motor 38, the other terminal ofthe motor being grounded to complete. the return circuit to the battery.

In operation the switch parts will normally be in the position shown inFig. 1 when the heater is cold and the control knob 46 is in "offposition. In this position the control knob 46 abuts against theextension of arm 64 and holds the contacts 64, 86 separated, and holdsthe contact 96 away from the contact 86. Thus, neither the igniter northe fan is supplied with current.

When it is desired to initiate operation of the heater, the controlbutton 46 is pulled outwardly from the position which is shown in Fig.1, to the position shown in Fig. 2, whereupon the switch arm 66, due toits inherent resiliency, will swing to the left (Fig. 2) to complete thecircuit through the contacts 68 and 84. With the heater cold thebi-metal contact strip 66 will, however, be unflexed, and contact willnot be established between the contact points 86 and 96.

After the heater has commenced operation and become heated to atemperature sufiicient to warrant the operation of the fan motor tocirculate air from the passenger compartment of the vehicle past theradiator, the bi-metallic thermostatic contact strip 66 will flexsufliciently to close the motor circuit by pressing the contact 86against the contact 96. Current will thus be supplied to the motor 38while it is still being supplied to the igniter through the circuitcompleted by the contacts 84 and 88. After a short period,

however, the iii-metallic th rm t tic switc arm 66 will exert more andmore pressure against the contact 96 as the radiator is raised to ahigher temperature, and as soon as the radiator attains contact rivet.96 will be pressed against the insulating strip I64 and thus furtherflexure of the switch arms will be prevented.

If, when the switch parts are in the position shown in Fig. 4, thecontrol button 46 is moved to the position in which it is shown indotted lines in Fig. 4, to shut off the heater, such movement of thecontrol button will not have any effect upon the switch parts, but willmerely close the valve 64 thus causing extinguishment of the flame inthe combustion chamber of the heater. Thereafter the fan motor 38 willcontinue to 0perate and the radiator will be cooled, delivering its heatto the air in the passenger compartment of the vehicle, until thebi-metallic switch arm 66 cools sufi'iciently to permit the extension ofthe resilient switch arm 66 to abut against the control button 46.Shortly thereafter, upon continued clockwise flexure of the bi-metallicswitch arm 66, the contacts 66 will be moved from the contact 96 and theparts will resume their normal inoperative position, as shown in Fig. l.

It will be noted that in the switch construction herein disclosed, thebi-metallic thermostatic switch arm 66, when heated, flexescounterclockwise, in the same direction that it would otherwise be movedby the control button in shutting off the heater. In fact, under normalconditions, the bi-metallic switch arm 66 is not subjected to anyexternally applied forces at any portion of its cycle of operation. As aresult, since the bi-metallic switch arm is'subjected only to thestrains incidental to changing temperature, it will maintain itsadjustment throughout the life of the heater and will operateeffectively to close and open the switch contacts at exactly the desiredtemperatures.

Due to the arrangement of theswitch contacts. the fan motor willcontinue to operate after the heater has been shut off, thus efficientlydelivering to the air in the passenger compartment of the vehicle theresidual heat of the radiator after the heater has been shut off.

Due to the simple arrangement of the switch contacts and the bi-metallicthermostatic element for operating the same, the initial adjustment ofthe thermostatic element for causing it to open and close the switchcontacts at the desired temperatures may be readily made,

merely by bending the thermostatic element slightly. After this initialadjustment has been made, there will be no occasion for furtheradjustment due to the fact previously mentioned,

that the bi-metallic thermostatic switch arm 66 is not subjected tostrainsfrom external forces.

While I have shown and described a particular embodiment of myinvention, it will be readily apparent to those skilled in the art thatnumerous variations may be made in the construction disclosed withoutdeparting from the basic principles thereof. I therefore desire toinclude in the following claims'all such modifications and variations aswill be readily apparent to those skilled in the art, and by whichsubstantially the results of my invention may be attained insubstantially the same way.

I claim:

1. In an automobile heater of the internalcombustion type, thecombination of a combustion chamber, electrical ignition meansassooiated with said chamber for igniting a combustible mixture ofliquid fuel and air therein, a radiator receiving the products ofcombustion from said chamber, means for withdrawing said products ofcombustion from said radiator under reduced pressure, a manuallyoperable valve for controlling the flow of the products of combustionthrough said radiator, an electric motor, a fan driven thereby forcirculating air past said radiator, and a switch mechanism forcontrolling the supply of electrical energy to said fan motor and tosaid igniter, said switch mechanism comprising a rigid contact arm, aresilient contact arm normally held from engagement with said rigidcontact arm by said manually operable control element and completing anelec' trical circuit to said igniter when said control element is movedto position to cause operation of the heater, a bimetallic thermostaticswitch arm cooperable with said resilient switch arm to complete anelectrical circuit for supplying power to said fan motor and operablewhen said radiator attains a predetermined temperature to move saidresilient switch arm from contact with said rigid switch arm and therebyopen the circuit to said electrical igniter.

2. In an automobile heater of the internal combustion type, thecombination of a combustion chamber, electrical igniting meansassociated with said chamber, a radiator heated by the products ofcombustion, means to promote a flow of fuel and air through saidcombustion chamber and radiator below atmospheric pressure, means forcirculating air past said radiator to be heated thereby, said meansincluding an electric motor, a manually operable control element forcontrolling the flow of the products of combustion through saidradiator, two pairs of switch' contacts, one pair being in series withsaid electrical igniter and the other pair being in series with saidelectric motor, a flexible conductor supporting two of said fourcontacts, temperature responsive means supporting another of saidcontacts and a rigid support for the fourth contact, and means operatedby said manual control element to close the pair of switch contacts inseries with said igniter, said temperature responsive means receivingheat from said radiator operable sequentially to close said electricmotor contacts and shortly thereafter to separate said igniter contactsas the temperature of said radiator passes through a predetermined rangeof temperature change.

3. In a switch mechanism for heaters of the internal combustion typeemploying a combustion chamber, a manually operable element to controlthe flow of fuel to said combustion chamber, electrical ignition means,a radiator, an electric motor driven ,means for circulating air pastsaid radiator, comprising: a relatively rigid support in a heatconducting relationship with said radiator, a relatively rigid contactarm, a resilient flexible contact arm', and a bimetal temperatureresponsive contact arm secured to said supporting plate and each arminsulated from the others and from said plate, means operable by saidmanually operable element to permit said resilient arm to engage saidrelatively rigid arm to complete a circuit to said igniter, and meansoperated by said bimetal arm to complete a circuit to said electricmotor when said radiator attains a predetermined temperature andthereafter to swing said flexible arm away from said relatively rigidarm, thereby to open the electrical circuit to said igniter.

4. A switch assembly comprising a support, a relatively rigid contactarm secured to said support, a flexible arm and a temperature responsivearm secured to said support between the latter and said relatively rigidarm, said arms being insulated from each other and from said support, apair of contact points carried by said flexible arm and facing in thesame direction, contact points respectively on said rigid arm andtemperature responsive arm engageable respectively with the contacts onsaid flexible arm, manually operable means to condition said flexiblearm for flexure toward said relatively rigid arm to close the electricalcircuit through the contact points thereof, said temperature responsivearm being adapted upon being heated to complete a circuit with saidflexible arm and upon continued rise in temperature to move saidflexible arm in a direction to open the circuit between said flexiblearm and said relatively rigid arm.

5. In a temperature responsive switch assembly, the combination of arelatively rigid contact point, a flexible arm carrying a contactcooperablewith said relatively fixed contact, a temperature responsiveelement adapted upon an increase in the temperature thereof to engagesaid flexible arm and make electrical contact therewith and operableupon a further increase in temperature thereof to separate the contacton said flexible arm from its associated contact on said rigid arm, anda manual control to flex said flexible arm to such a position that itcannot contact said rigid arm, but can contact said temperatureresponsive arm when the last said arm is at a high temperature.

6. In a switch device, the combination of a manual control elementmovable into at least two positions, a support, a relatively rigidcontact arm, a resilient contact arm, and a bimetallic contact arm, allof said arms supported by said support and electrically insulatedtherefrom and from each other, a contact point on said rigid arm, asecond .contact point on said resilient arm and facing the first saidcontact point, said second contact point adapted to touch the first saidcontact point when said resilient arm is free, a third contact on saidbimetallic arm and a fourth contact supported by said resilient arm,said manual control when in one position adapted to engage and flex theresilient arm away from the rigid arm and in a second position to beremoved from contact with the resilient arm and allow the first andsecond of said contacts to close, said bimetallic arm when heatedadapted to close the third and fourth of said contacts and upon furtherheating to flex the resilient arm away from the rigid arm and open saidfirst and second contacts while maintaining the third

